The German Nazis were the world’s most powerful and influential fascist organisation, and they were also the most anti-Semitic. Their Jew-hating world view was remarkable because it was so irrational, yet it became the official ideology of a modern, powerful state.

They believed their own lies so fervently that even as their empire was being blasted into rubble, Nazis stretched their supply lines and diverted military resources to a campaign of genocide using the most advanced industrial methods. They thought a global Jewish conspiracy was behind anything new, any intellectual or cultural advance, any discontent of modernity, any military or political rival to the Third Reich: from Roosevelt to Churchill, by way of Stalin, Trotsky, suffragettes and cubism. The pathetic insanity of the world view went hand in hand with the extremity of its violence.

At the time, socialists marvelled that the apparently primitive, superstitious Jew baiting was promoted by such a technologically advanced state. But in the decades since the defeat of the Nazis, their form of anti-Semitism has come to look like a historical curio, a relic of an ancient European culture that had yet to rid itself of all its medieval prejudices.

Jewish political culture has changed almost beyond recognition since the time of the Third Reich. Between them, Hitler and Stalin nearly wiped out European Jewish revolutionary socialism. Fewer diaspora Jews live in Yiddish-speaking concentrations. The national identity of Jews is now linked to a nuclear-armed, imperialist nation-state. Israel’s government is a faithful friend to right-wing nationalists around the world.

But fascist politics still circles back to anti-Semitism. In the minds of fascists, Jews remain what they always were: the shadowy figures behind every modern problem, real or imagined. In US fascist politics, mass migration is the heavy artillery of a Jewish plot for total domination: a “great replacement” of whites by their racial inferiors.

The conspiracy theory survived the Holocaust and the defeat of the Nazis. The worst mass killing of US Jews didn’t take place in 1930s, when the Nazi front group, the German-American Bund, campaigned against Roosevelt’s “Jew Deal”. It didn’t take place in the 1960s, when the re-formed Ku Klux Klan organised murders of Jewish activists travelling south to campaign for civil rights. It didn’t take place in the 1980s, when US Nazis turned to gangsterism and violent bank robbery, assassinating Jewish liberals like Alan Berg along the way. It happened a couple of weeks ago in Pittsburgh. The perpetrator had learned his old-fashioned Jew hatred from the memes and podcasts of the very modern “alt-right”.

Not all fascists are anti-Semites, but fascism has a tendency towards anti-Semitism. Fascism accepts all the myths of capitalism and turns them into immutable, eternal truths. It makes a grand religion out of the fairy tales of conservative common sense. For conservatives, race is real, nations are natural, and gender roles flow from biological necessity. All these “traditions” are modern inventions, but conservatism makes them timeless truths.

For fascists, they become even more than that. Nation and race become the centre of a theory of history: human existence is a struggle of nations, races and perhaps religions. Divisions within nations – such as white leftists who work in solidarity with non-white migrants – have to be explained away, and they have to be explained according to the logic of race and nation.

Unpatriotic whites can’t just be evil: if whites can be evil, the whole logic of racial nationalism breaks down. They have to be dupes. Fascist logic needs a great enemy: an anti-national nation, a race of people who undermine racial solidarity. In the fascist imagination, that is the role of Jews.

The killing of Jews in Pittsburgh has sparked two debates that are closely intertwined. Is Trump, along with the broader Trumpified right wing political movement, responsible somehow for the massacre? And how should Jews respond to the re-emergence of violent anti-Semitism in the United States?

To the first question, we say simply: yes. Trump, the Trumpified Republican Party, and the Trumpified international centre-right have spent years promoting a world view in which all opposition is part of a conspiracy of degeneracy and subversion.

As his 2016 campaign came to a close, Trump began to describe Hillary Clinton as merely the “vessel for all of the global special interests”. Throughout his presidency, Trump and his defenders claimed that left wing protesters were funded by Jewish capitalist George Soros. Campaigns for gender and sexual equality are now routinely described by right wing commentators as “cultural Marxism”, an ideological infestation that breaks down sexual morality and weakens the bonds of nationhood.

In the lead-up to the 2018 midterm elections, Trump and the Republicans began to focus heavily on the “caravan” of mostly Honduran refugees and displaced peasants, alleging not only that it was full of murderers and Arab terrorists, but that it was covertly funded by Democrats and possibly by Soros.

The framing is nauseatingly familiar to us now. It’s shared by an international movement of right wing politicians. Not all are fascists or anti-Semites. But the logic of their argument trends in a particular direction. Our nation – or our race – must be unified. But it is not unified but disintegrating, not because of its own weakness, but because of the influence of shadowy, powerful figures.

The conservative press might campaign against transgender rights and immigration, but those are only the symptoms of some deeper process that must be unmasked and eradicated. And if mainstream conservatives won’t do it, someone has to follow the logic to its conclusion.

Robert Bowers determined that Jews were behind the “invaders” spoken of so much by Trump and the conservative press. “There is no #MAGA as long as there is a kike infestation”, he wrote on his social media profile, shortly before massacring 11 Jews in Pittsburgh.

The political logic of fascism creates a breeding ground for anti-Semitism. And that’s true even if Trump says he’s the greatest friend Israel has ever known, even if extreme Zionists promote themselves amongst the international far right and even if the Israeli government displays such extreme racial chauvinism that US Nazis like Richard Spencer express grudging admiration for it. That leads to certain obvious conclusions for Jews around the world.

For years now, right-wing Zionist activists – Jewish and gentile – have played cynical games with very serious issues.

On the one hand, false accusations of anti-Semitism have been freely conjured up, with no basis in fact, in order to slander and discredit the most consistent anti-fascists in the world: the socialist movement.

This reached new heights of absurdity in 2018, as Jewish and non-Jewish Zionists in Britain whipped up an utterly baseless panic, for the third year running, targeting Jeremy Corbyn and his supporters in the Labour Party. For months in 2018, the British and international press were consumed with hyperventilating about a purported infestation of anti-Semitism in the British left. But at the end of the year, it was not a Corbyn, or any other leftist supporter of Palestinian rights, who massacred Jews in Pittsburgh.

Meanwhile, the Zionist right has feted and cultivated the far right and fascistic figures whose rise has coincided with the re-emergence of exterminationist anti-Semitism. The Israeli government has built close ties with those demagogic campaigners against “globalism” and “cultural Marxism”: Trump, Hungary’s Viktor Orban and Brazil’s Bolsonaro. All, like the Israeli government, are nationalist authoritarians. As Zionists legitimise and promote these figures, they fan the flames of a modern anti-Semitism.

We Jews can find no comfort in the rise of political movements that seek to hunt down and eradicate secret “globalists”, even if their figureheads shake hands and make military alliances with Jewish nationalists.

Jews must ally with the anti-fascist left, not the authoritarian right. To really fight anti-Semitism, we have to name and confront the far right politics that engenders it.